Merge pull request #7 from yuezhao/master

Fix Lab color mode with 3 channels. Add support for lab color mode with 4 channels.
Added support for Lab color mode
Editted license
Added Qt5 support

added Qt5 support
separated QPSDPlugin and QPSDHandler into separate files
Added PSB support

Added PSB support
Changed QPSD prefix to QPsd for Qt coding style
Restored license file
Minimized Lab to RGB conversion bug

Tried to repair Lab to RGB conversion bug: output RGB goes outside the
range 0-255 which causes the bug. Found out tha alpha color is
transparent at 255 and opaque at 0. Bitmap color mode was skipped in
line 202 of qpsdhandler.cpp.
Minor fix: Lab to RGB computation

Used http://www.brucelindbloom.com/ computation formula and Adobe RGB
data (matrix, etc). Used Gamma companding instead of sRGB companding
Speed improvement/optimization

Speed improvement in reading color mode data section and image data
section
Added Multichannel Support (3 & 4 channels)

Added Multichannel support (3 & 4 channels)
Renamed members for Lab to RGB computations into camelcase style
Repaired Lab to XYZ to RGB conversion algorithm

Repaired Lab to XYZ to RGB conversion
Improved speed of copying data from QDataStream to QByteArray
BUGFIX: a bug on QImageIOPlugin::capabilities