chore(version): bump version number to v1.5.2

chore(version): bump version number to v1.5.1

docs(javadoc): fix param name in sendJsonPayload javadoc

Closes PR rollbar#180

Release 1.4.1

Release 1.4.0

Merge pull request rollbar#163 from rollbar/release-1.3.1

Release 1.3.1

Merge pull request rollbar#160 from rollbar/release-1.3.0

Release 1.3.0

Merge pull request rollbar#151 from rollbar/release-1.2.1

Release 1.2.1

Release v1.2.0

Merge pull request rollbar#127 from rollbar/prepare-release-1.1.0

Prepare to release 1.1.0