When using -g hint the WM that we've got user specified geometry

Without this some window managers (e.g. fvwm) will ignore the initial
window position and place it according to it's own rules.
Updated/corrected license header
Refactored function definitions to use dangling brace
Be honest about using C99
Use bool from stdbool.h after switching to C99
Correctly updated window pixmap after i_fit_to_img()
Merge remote-tracking branch '4z3/set-user-specified-sizehints' into sizehints

Conflicts:
	window.c
Refined US{Position,Size} & WinGravity handling
Correctly set window height after i_fit_to_img()
Set minimum acceptable window size to 16x11 ^_^
Merge remote-tracking branch 'muennich/sizehints'
Merge branch '16x11'