Add Parse*Geometry methods (gographics#304)

* Implement Parse*Geometry methods

This required changing the implementations of GeometryInfo and RectangleInfo to match their C struct counter parts.

* Expose QUANTUM_RANGE

* Add ParseAbsoluteGeometry(string, *RectangleInfo)

* Add ParseRegionGeometry/ParsePageGeometry

* More accurately wrap Parse*Geometry APIs

* Add func documentation

Disable unused C field causing type error in ImageMagick 7.1.1-24 (fixes

 gographics#301)

Merge branch '295_MagickAutoThresholdImage' into im-7

# Conflicts:
#	imagick/magick_wand_image.go

Merge branch '229_win_fdopen' into im-7

Fix windows fdopen error (refs gographics#229)

GetTextInterlineSpacing should call correct C api function (refs gogr…

…aphics#282)

GetTextInterlineSpacing should call correct C api function (refs gogr…

…aphics#282)

Add check for cols/rows params to avoid divide-by-zero error (SIGFPE)…

… in C (refs gographics#278)

(IM6) Add check for cols/rows params to avoid divide-by-zero error (S…

…IGFPE) in C (refs gographics#278)

Merge branch 'im7_SetImageMask' into im-7