Don't use the $LINGUAS at configure time to set ALL_LINGUAS, and let
the translations Makefile properly honor the $LINGUAS itself, which it
already does better than we do, cleanly ignoring translations it
doesn't know.

If we do set ALL_LINGUAS=$LINGUAS, it will result in a build failure if
we do not have a translation for some of the language(s) specified in
$LINGUAS, and would make it impossible to build other languages without
re-configuring.  So, just drop that part and let the build-time support
kick in.

Closes #507.

Patch partly from Yosef Or Boczko, thanks.  Closes #959.

Closes #1062.

`entries_modified` global is only used by on_name_entry_changed() and
on_entries_changed(), both of which are only ever called from
project_new() scope -- which already initializes this variable.

Having add_input_widgets() didn't really make the code any simpler,
rather obfuscating it a little.

Use gtk_dialog_run() to run the key input dialog, which is modal anyway.
This avoids having to pass the label and the iter around for the dialog
response callback to have them, as they now only are used directly in the
function setting them in the first place.

This however doesn't get rid of any of the global data itself, it only pack it
in a struct and passes pointer to this struct around instead of accessing the
global whenever possible.

Apparently the ::unrealize symbol is sent too late, after we destroyed
the widget and freed the GeanyDocument, and some signals like
::focus-in-event can still be fired on the widget after that.

So, properly use the ::destroy signal that is supposed to be fired when
others should release references to that instance.

Properly skip parentheses around an rvalue, and then properly recognize
the surrounded value.  This allows to properly recognize e.g. rvalue
`({...})` as an object, or `(function(){})` as a function.  As the
implementation is tolerant regarding garbage after the statement,
function expressions called straight away (`(function(){})()`) are
implicitly supported.

This however removes support for the following invalid JavaScript
syntax that was previously supported as a function/method declaration:

	var func = () {}

This syntax is not present in the ECMA standard nor is supported by
popular JavaScript engines.

See:
 * http://www.ecma-international.org/publications/files/ECMA-ST/Ecma-262.pdf
   section 13, "Function Definition"
 * http://ecma262-5.com/ELS5_HTML.htm#Section_13
 * https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions_and_function_scope#Defining_functions

Just cleaning up last commit.

Mostly gets rid of re-drawing issues, however is not great.

Fix typo in documentation