Allow all X-Imbo-* headers on CORS-requests
Made CORS-listener have a higher priority than AccessToken/Authenticate-listeners
Merge pull request #298 from rexxars/cors-allow-imbo-headers

Allow Imbo-headers for CORS-requests
Added configuration option (`contentNegotiateImages`) which allows disabling content negotiation for images.
Updated ChangeLog
Grammar improvements
Merge pull request #300 from rexxars/config-content-negotiate-images

Allow disabling content negotiation for images
Make sure we have a working PDO instance before clearing temp tables in the tearDown. Fixes #302.
Merge pull request #303 from androa/issue-302

Make sure we have a working PDO instance before clearing temp tables
Started work on two new image transformations: sharpen and contrast
Added contrast and sharpen transformations
Use the unsharpMaskImage method for sharpening, and introduce gain and threshold params
Added sharpening presets
Fixed indentation
Added docs for contrast and sharpen
Added a unit test for the different presets, and set default values for all params for all presets
Added a test to make sure the preset values can be overridden, and also corrected default values
Updated ChangeLog. Fixes #264 and #265
Updated ChangeLog
Merge pull request #266 from christeredvartsen/contrast-and-sharpen

New image transformations: contrast and sharpen