tracker-preferences: Added reindex function, require GTK+3 & fix optical disc sensitivity.

- Glade file required older GTK+ 2.x version, but we require 3.x in the code
  base.

- The index optical discs checkbutton was not correctly insensitive at the
  right times.

- We now have a "system" page to reindex our data if users want an easy way to
  do this.
Updated Polish translation
Updated Galician translations
Updated Czech translation
Updated Hebrew translation.
Fix typos in tracker-search man page

A few of the short options were misspelt.

https://bugzilla.gnome.org/show_bug.cgi?id=703097
Updated Brazilian Portuguese translation
Updated Traditional Chinese translation(Hong Kong and Taiwan)
Removed markup from UI files
Updated Spanish translation