Viewer Error Messages improvements

Added error icon image

Modified gitignore

Added bootstrap styles and updated widget classes

Re-styled notification widget

Using generic GWT version (latest)

Adding new space char to linker

Split widget and panel into 2 classes

Enum with text strings for different notifications

Updated display registration widgets

Updated references to notification and registration widgets

A retry counter for certain messages

Object cleanup

Not showing notifications if Viewer has data

Incrementing app engine version

Moved Use Google Chrome notification

Fixed hide issue

Added variable delay timers
Updating button styling
Updated Display Registration text
Merge pull request #7 from alex-deaconu/feature/error-improvements-ui

Re-styled Notification and Display Registration widgets