Add model to track and send errors
Track method errors
Track subscription errors
Test error model
Send uncaught exceptions to kadira (immediately)
Use e.message as error name
Add method/sub name to source
Check is callback exists and if it's a function
Do not check callback type

Don't check whether callback is a function Let the program fail.
Send error trace
Use type:message as key when storing errors
Remove redundant data (error time and events)
Fix error and rename stack to stacks
Merge branch 'mnmtanish-error-model' into error-tracking
Merge remote-tracking branch 'origin/error-tracking' into error-tracking