v0.5.0

• Renamed add action to capture, (using add still works for now, but it's deprecated)
• Default threshold is now 0
• Refactored out the external ImageMagick dependency, now using BlinkDiff
• Added timestamping to the verbose logging level
• Performance: Now creating just 1 PhantomJS instance per page/url, instead of per 1 instance per component. (#11)
• Performance: Now running PhantomJS in parallel, also added concurrency as an argument (6b385c5, #11)
• Performance: now getting image size without loading it the entire image into memory
• Tests: Replaced express with http-server (#8)
• Fix: It's now possible to use a threshold of exactly 0 (#2)
• Fix: Mapping between left and right fullpaths are now safe (1b61ab5)
• Fix: Non-fatal errors in PhantomJS are now allowed (84fc386)
• Fix: identifiers are now slugified, supporting all characters (d350452)