Fix #1 language string not found errors

e.g. APPLICATION WARNING #300: String "plugin_releasemgt_releases_link"
not found.

The language strings variables names must exactly match the plugins's
name (i.e. 'releasemgt' != 'Releasemgt')

Signed-off-by: Damien Regad <dregad@mantisbt.org>
Added German translations

Signed-off-by: Damien Regad <dregad@mantisbt.org>
Fix corrupted download for filenames with spaces

Signed-off-by: Damien Regad <dregad@mantisbt.org>
Add .gitignore and exclude netbeans project files
Revised file headers

Also fixed missing newline at end of files, and removed closing ?> tags.
Replace occurences of deprecated `db_query` API

In MantisBT 1.3, the db_query() function will be removed from the API,
so replacing occurences by db_query_bound().

Fixes #1
Simplify boolean return value
Change plugin URL to Github

It was still pointing to old Google Code project.
Bump version to 1.2.1