Help projectionist find .projections.json in new directories

I have an auto-mkdir thing for writing files in directories that don't exist, and projection templates are not applied to files in non-existent directories (and actually, vim-projectionist just fails to find .projections.json in this case). They are if I `mkdir` first though.

Example:

**Projection**

```
{
  "foo/*.js": {
    "template": [
      "blah"
    ]
  }
}
```

If I do `vim foo/bar.js` the template is used; if I do `mkdir foo/bar/ && vim foo/bar/baz.js` the template is used. But if I do `vim foo/bar/baz.js` by itself I don't get the template.

Here's why it matters: angular and react and some other frameworks advocate a directory-per-component structure, so any new component is in a new directory. Your structure ends up looking like:

```
components/
  foo/
    foo.js
    foo.html
    foo.test.js
```

so every time you create a new component you're creating a new directory. Which means I either _never_ get the benefit of auto-mkdir (and have to type `mkdir` every time . . . I know, I know, first world problems) or I _never_ get the benefit of a projection template.

This turned out to be because `expand('<afile>:p')` doesn't result in an absolute path in non-existent directories. This change fixes it by detecting non-absolute paths and prefixing them with cwd.

Thoughts?

Author: tandrewnichols

plugin/projectionist.vim

@@ -25,9 +25,14 @@ function! s:has(root, file) abort
 endfunction
 
 function! ProjectionistDetect(path) abort
+  let path = a:path
+  if path !~ '^/'
+    let path = getcwd() . '/' . path
+  endif
+
   let b:projectionist = {}
   unlet! b:projectionist_file
-  let file = simplify(fnamemodify(a:path, ':p:s?[\/]$??'))
+  let file = simplify(fnamemodify(path, ':p:s?[\/]$??'))
 
   let root = file
   let previous = ""