Update and remove obsolete application desktop files

Some XDG application `.desktop` files are not required anymore because
the latest upstream versions have been adapted and improved to match the
custom configurations:

>> JetBrain Products

* "JetBrains IntelliJ IDEA Ultimate Edition" (1) binary
`/opt/intellij-idea-ultimate-edition/bin/idea.sh` is now linked to
`/usr/bin/idea` and `/usr/bin/intellij-idea-ultimate-edition`. The
desktop file is now named uniform
`/usr/share/applications/jetbrains-idea.desktop`.
* "JetBrains IntelliJ IDEA Community Edition" (2) binary
`/opt/intellij-idea-community-edition/bin/idea.sh` is now linked to
`/usr/bin/idea`. The desktop file is now named uniform
`/usr/share/applications/jetbrains-idea.desktop`.
* "JetBrains Webstorm" (3) binary `/opt/webstorm/bin/webstorm.sh` is now
linked to `/usr/bin/webstorm` and the desktop file is now named uniform
`/usr/share/applications/jetbrains-webstorm.desktop`.
* "JetBrains Pycharm Community Edition" (4) binary
`/opt/pycharm-community-edition/bin/pycharm.sh` is now linked to
`/usr/bin/pycharm`, bu the desktop file is still named
`/usr/share/applications/pycharm.desktop`.

>> Atom

* "Atom 1.28" (5) included an upgrade to Electron 2.0 and now ships with
an standalone launcher(`/usr/lib/atom/atom`) instead of using the
Electron binary (`electron <BINARY_PATH>`).

References:

  (1) https://aur.archlinux.org/cgit/aur.git/tree/jetbrains-idea.desktop?h=intellij-idea-ultimate-edition
  (2) https://git.archlinux.org/svntogit/community.git/tree/trunk/idea.desktop?h=packages/intellij-idea-community-edition
  (3) https://aur.archlinux.org/cgit/aur.git/tree/jetbrains-webstorm.desktop?h=webstorm
  (4) https://git.archlinux.org/svntogit/community.git/tree/trunk/pycharm.desktop?h=packages/pycharm-community-edition
  (5) http://blog.atom.io/2018/06/21/atom-1-28.html#electron-upgrade

Closes GH-118

snowblocks/plank/launchers/archbook/jetbrains-idea.dockitem

@@ -0,0 +1,2 @@
+[PlankDockItemPreferences]
+Launcher=file:///usr/share/applications/jetbrains-idea.desktop

snowblocks/plank/launchers/archbook/pycharm.dockitem

@@ -0,0 +1,2 @@
+[PlankDockItemPreferences]
+Launcher=file:///usr/share/applications/pycharm.desktop

snowblocks/plank/launchers/igloo/jetbrains-idea.dockitem

@@ -0,0 +1,2 @@
+[PlankDockItemPreferences]
+Launcher=file:///usr/share/applications/jetbrains-idea.desktop

snowblocks/plank/launchers/igloo/pycharm.dockitem

@@ -0,0 +1,2 @@
+[PlankDockItemPreferences]
+Launcher=file:///usr/share/applications/pycharm.desktop

snowblocks/xdg/applications/atom.desktop

@@ -2,9 +2,9 @@
 Type=Application
 Name=Atom
 Icon=atom
-Exec=electron --app=/usr/lib/atom %F
+Exec=/usr/lib/atom/atom %F
 StartupNotify=true
-MimeType=text/plain;text/css;text/java;text/md;text/markupdescription;text/readme;text/h;text/c;text/cpp;text/cp;text/js;text/xml;text/schema;text/x-sass;text/x-less;
+MimeType=text/plain;text/css;text/java;text/md;text/markupdescription;text/readme;text/h;text/c;text/cpp;text/cp;text/js;text/xml;text/schema;text/x-sass;text/x-less;text/markdown;
 Actions=dev-mode;
 
 [Desktop Action dev-mode]

snowblocks/xdg/snowblock.json

@@ -46,16 +46,6 @@
         "force": true,
         "path": "applications/gtkhash.desktop"
       },
-      "~/.local/share/applications/intellij-idea-ce.desktop": {
-        "create": true,
-        "force": true,
-        "path": "applications/intellij-idea-ce.desktop"
-      },
-      "~/.local/share/applications/intellij-idea-u.desktop": {
-        "create": true,
-        "force": true,
-        "path": "applications/intellij-idea-u.desktop"
-      },
       "~/.local/share/applications/minecraft.desktop": {
         "create": true,
         "force": true,
@@ -71,21 +61,11 @@
         "force": true,
         "path": "applications/org.gnome.Screenshot.desktop"
       },
-      "~/.local/share/applications/pycharm-community.desktop": {
-        "create": true,
-        "force": true,
-        "path": "applications/pycharm-community.desktop"
-      },
       "~/.local/share/applications/shotwell-viewer.desktop": {
         "create": true,
         "force": true,
         "path": "applications/shotwell-viewer.desktop"
       },
-      "~/.local/share/applications/webstorm.desktop": {
-        "create": true,
-        "force": true,
-        "path": "applications/webstorm.desktop"
-      },
       "~/.config/autostart/dropbox.desktop": {
         "create": true,
         "force": true,