ui: replaced confusing Voice settings labels, fixes #226
ui: updated tooltips of Game and View options

This adds missing tooltips, and uniformizes the various labels.
ui: updated r_mode 12 label to 1366x768, ref #110

The r_mode 12 value has been changed from 1360x768 to 1366x768.
general linux: warning fix fixes #277
renderer: rounding conversion for lod refs #247
misc: add linux support for et:// protocol, fixes #269

This provides necessary files for Freedesktop XDG protocol handling.
Linux client: avoid "MODE is unbound, use controls menu to set" print
fixes #158
Merge pull request #39 from Spyhawk/etprotocol

misc: add linux support for et:// protocol, fixes #269
Merge pull request #37 from Spyhawk/mycode

ui: various minor fixes
ui: updated voice settings labels
added possibility for ETLegacy to join on IRC server
Uploaded missing file
client: FEATURE_IRC_CLIENT