Compiler warning fixes
 - unsigned/signed comparisons
 - unused vars
 - var init ordering
 - missing cases in switches
Merge pull request #74 from asmaloney/compiler_warning_fixes

Compiler warning fixes
'Absolute' color scales are now available.
STL files can now be saved in both BINARY and ASCII formats
PLY files can now save/handle materials as properly as possible
Using now "texcoord" for PLY texture coordinates field (as PhotoScan)
New way of handling SF display parameters (in progress)
New color scale mechanism upgraded/fixed
missing cast was preventing compiling on linux
New color ramp display
Merge remote-tracking branch 'origin/master'
Color ramp display upgraded + log scale is now correctly handled