Merge pull request gumlet#184 from pluc/master

Replacing deprecated null parameter gumlet#3 of imagerotate() by 0

Merge pull request gumlet#181 from Internacionalweb/fixed-return-getc…

…ropposition

Modified return type to avoid implicit float to int conversion

fix for 7.1

Merge pull request gumlet#132 from lefuturiste/master

add gamma correct option

Fix gamma correction

Coveralls added correctly

prepared readme for 1.8.0 version

Merge pull request gumlet#93 from hultberg/eh-suppress-error-exif

Suppress exif_read_data errors