Do not need otp-custom_ttsl_drv since R16B.
Fixed extensions.
Fixed extensions. Added extension points 'prompt' and 'startup_msg'.
Merged updates from R16B01
Merge branch 'power-kjell' of https://github.com/karlll/kjell into power-kjell

Conflicts:
	src/kjell_extension.erl
Fixed unicode text in ansi strings.
New attributes in etcol.
Fix failing test case
Add extension point 'startup'
Handle prompt containing escape chars
Check if extension is loaded.
Minor update
Improved logging
Added get/set_value tests
Updated log functionality
Fix issue w. losing state when loading profile
Minor edits
Bumped version
Added log levels
Added extensions sub module