Update CHANGELOG for 0.3.0
Unnecessary contract removal

- Removed unneccessary ContractManager, but left the non-empty string
  checks until they are replaced with a better solution. (cofoja)
- Fixes #42
Re-added gitignore

This got removed during some trivial merge into master.
Updated Jackson library to 2.4.1.1

- Fixes #38
New Payload interface that properly maps to only a payload
Added timestamp support into trackers

- Fixes #26
Newline between license and package
Added support for context as maps

- Fixes #11
- Note that we've used the interface Map and not HashMaps in particular to give the option for users
Removed support for context as a string

- Fixes #44
Fix for warnings
Fix for warnings & unused code
Replaced println with SLF4J

- Added some basic logging for trackers when sending events, and HTTP messages being sent.
- Fixes #15
Semi-colon fix
Revert "New Payload interface that properly maps to only a payload"

This reverts commit c5e21f829360b299e6ce2a1f6fe281be5bf69554.
Initial PayloadMapC tests

- Incomplete for #34
SLF4J upgrade to fix warning

- 1.7.5 -> 1.7.7
- Adding slf44j-simple in replace of slf4j-api (also installed either way), fixes this
Fix missing else statement in setTimestamp
Util tests + more Payload tests

- Fixes #34
- Fixes #35
Minor comment tweaks + unused imports
Removed unused methods