Blender Git Loki

* Added WM_operator_filesel which can be used for an operators invoke function (like WM_operator_confirm).
It opens the files selector if "filename" property has not been set, else it executes the operator directly. Brecht, you might want to check, currently only sequencer add operators use it.
* Added back Effects menu back, replaced SEQUENCER_OT_add_color_strip with SEQUENCER_OT_add_effect_strip.
* Made sequencer header use operator UI functions.
* gcc complains when char's are used as array indicies when they are not explicitly signed/unsigned, corrected previous change for vpaint to silence this error.