minor fixes: line segment and polygon functionality, color, bookmark cog functionality added

minor bug fixes related to line segment, poly color and bookmark edit…

…ing functionality

Line segment added

v0.6.3

line segment included; which is selectable and exportable too

Export functionality completed

v0.6.2

stroke export included

Camera positioning - details edited

camera position FOV fix; canvas edit frame - ATs fixed; photo data in…

…cluded in osgt files.

Manual camera positioning added

Manual camera positionning added; canvas orientation bugs fixed; canv…

…as tool auto-scaled added; homography code added; docs fulfilled and updated; intersectors organized.

Polygon and stroke shaders added

shader added for polygon type, look at canvas bug fixed, minor code r…

…e-organization, doxygen generation done automaitcally, no sample demo provided

Polygon type added, in a demo mode

• Added polygon type
• Added scene demo of strawberry hill image

v0.5.0: stroke shadering added, fog factor introduced, unified cursor sizes, …

…singleton design introduced in main window

v0.4.2: bookmarks include scene state, its functionality is complete; some un…

fixed #66

v0.4.1: high dpi issues are fixed, bookmarks include FOV data, icons are adde…