Add FSEEK_END and negative offsets for FS_Tell.

Note, this worked for the text file I tested, but not sure how it will perform in other tests.
Change custom FOV instantly.

Rationale:
 - Previous system caused issues when switching between different classes on spectators.
 - The initial fear of zoom binds is unwarranted. Changing from 140 to 80 does not provide any advantage. In fact, it is quite disorienting.
Don't bother setting animation frames when rendering a thirdperson weapon.

This also gets rid of the "R_AddMDVSurfaces: no such frame %d to %d for '%s' (%d)\n" spam when developer mode is on.
FS_filelength correctly reports the size of files inside paks
Correctly report success/failure when using FS_SEEK_END
Merge pull request #1 from Unvanquished/master

Merge master into bugfix/ui
Menu color change, some clean up of the .menu files, menu order change

Changelog:
Removed the redundant use of "forecolor 1 1 1 1" from all menu files.
Changed the UI color scheme to closer match that of the website, logo, and game background.
Rearranged the options menu so that the graphical settings make more sense.
Created a new system sub category called "Effects"
Updated the presets to include all graphical effects and insured that all pre-exsisting effects had 'uiScript glCustom' so that the preset is correctly changed to Custom upon changing a setting.
Added in motion blur as a setting
Fixed some whitespace that Velo pointed out that Notepad++ missed
Accidentally merged an older, out of date version of this file

This is the updated file
Fixed some more whitespace
This should be last of the whitespace errors
Fix compilation