End-of-line normalization
OS X Mavericks build fixes.

Mavericks changed the way codesign tool works, it now requires
sub-frameworks and binaries to be signed too. This means signing must be
done as part of build process and cannot be done after the fact.

Still compile Poedit w/o signing by default, but add code to behave
correctly if a signing identity is set.
Fix wrong font for TM stats on OS X.
Fix opening already-open files on case-insensitive systems.

When the user opens a file, Poedit checks if it is already open and
doesn't open another window if the file already has one.  Unfortunately,
this test was broken: it used string comparison, which was case
sensitive (wrong on Windows and OS X) and didn't account for
normalization, symlinks etc.

Use wxFileName::operator== instead.
Raise editor window when re-opening already open file.

This is the standard behavior everywhere: there would be no feedback to
the user otherwise.
Fix editable source text fields on OS X.

These should be read-only, but due to a bug in wxCocoa, disabling and
re-enabling the controls would make them editable again.  The workaround
is easy: this code is no longer needed in the first place.
Fix plural form for Scottish Gaelic.

The value was completely wrong.
This is the standard form that should be used.