Add InspectSymbols command

[theofidry]

New command:

$ bin/php-scoper inspect-symbol --help
Description:
  Checks the given symbol for a given configuration. Helpful to have an insight on how PHP-Scoper will interpret this symbol

Usage:
  inspect-symbol [options] [--] <symbol> [<type>]

Arguments:
  symbol                         The symbol to inspect.
  type                           The symbol type inspect ("class", "function", "constant", "any"). [default: "any"]

Options:
  -d, --working-dir=WORKING-DIR  If specified, use the given directory as working directory.
  -c, --config=CONFIG            Configuration file. Will use "scoper.inc.php" if found by default.
      --no-config                Do not look for a configuration file.
  -h, --help                     Display help for the given command. When no command is given display help for the list command
  -q, --quiet                    Do not output any message
  -V, --version                  Display this application version
      --ansi|--no-ansi           Force (or disable --no-ansi) ANSI output
  -n, --no-interaction           Do not ask any interactive question
  -v|vv|vvv, --verbose           Increase the verbosity of messages: 1 for normal output, 2 for more verbose output and 3 for debug

Examples:

$ bin/php-scoper inspect-symbol GRAPHEME_EXTR_MAXCHARS constant

Internal (configured via the `excluded-*` settings are treated as PHP native symbols, i.e. will remain untouched.
Exposed symbols will be prefixed but aliased to its original symbol.
If a symbol is neither internal or exposed, it will be prefixed and not aliased

For more information, see:
 * Doc link for excluded symbols
 * Doc link for exposed symbols

Inspecting the symbol GRAPHEME_EXTR_MAXCHARS for type constant:

 * Internal: true
 * Exposed:  true

Another example:

$ bin/php-scoper inspect-symbol GRAPHEME_EXTR_MAXCHARS

Internal (configured via the `excluded-*` settings are treated as PHP native symbols, i.e. will remain untouched.
Exposed symbols will be prefixed but aliased to its original symbol.
If a symbol is neither internal or exposed, it will be prefixed and not aliased

For more information, see:
 * Doc link for excluded symbols
 * Doc link for exposed symbols

Inspecting the symbol GRAPHEME_EXTR_MAXCHARS for all types.

As a class:
 * Internal: false
 * Exposed:  false

As a function:
 * Internal: false
 * Exposed:  false

As a constant:
 * Internal: true
 * Exposed:  true