Compare two images keyword and optional image name option for capture keywords

[jessezach]

• Added an optional name argument to all capture keywords. Images can be saved with a user specified name
• Added an optional redact argument similar to blur. This will allow redacting content from images specially when blurring content doesn't help.
• Updated the autogenerated image report to have relative path to images instead of absolute.
• Added a new keyword called compare two images. This will allow comparing two different images captured during the test.
• Fixes related to separator