Spanish translation

[jmzlx]

Some sections are apparently not translatable. For example:

• The "New Issue" button on the upper right section of the project has a background image (newissue.png) which overlays the link's text.
• In the project list the tabs' text is generated by placing the adjective first and the noun later (Active Projects and Archived Projects). Both should be whole translatable strings since in spanish the adjective should go after the noun in this case (Proyectos Activos y Proyectos Archivados).
• The "Users" screen does not seem to be translatable.

I would like to confirm if I should report this as a bug that could be fixed in a separate pull request. I apologize for this beforehand since this is my first contribution (hopefully of many more).

[mendozafilm]

For the "New Issue" and "New User" buttons see: #208 .
The "Users" text comes from the database...