Implemented Photon and Readout Noise for WFS.
Updated noise strengths, fixed photon noise (Poisson)
Update wfr_doc.tex
Spell check and added some comments
Fixed bugs, one for messages when overiding certain values and other the bug in the tilt.
Merge branch 'master' of https://github.com/faitdivers/pyao into iss47

Conflicts:
	doc/WFR/wfr_doc.tex
Merge branch 'iss47' of https://github.com/faitdivers/pyao into iss47
Merge pull request #79 from faitdivers/iss47

Iss47
Bug fix for wrong arrangement of arguments.
Merge pull request #83 from faitdivers/WFS_iss57

WFS_iss57 Sensor Noise Implementation
Everything seems ok!
Fixed conflict in mainWFS.py
Merge pull request #85 from faitdivers/WFSBugFix

Fixed bugs in WFS
merge with master and resolved conflicts in wfr_doc.tex