[#165] Update release notes
[#167] Add warning upon lack of responses
[#167] Save responses more efficiently

* Cache and store responses as soon as we get them
[#166] Replace default colour

* Use black instead of white
[#166] Avoid IndexOutOfBounds exceptions

* Use modulo operator
Merge pull request #168 from akvo/issue/166-colors

Code checked and correct. Comment in resource is not quite grammatical...
Merge pull request #169 from akvo/issue/167-empty-form

Code checked and correct
[#160] Revert all-caps policy
[#160] Remove unused imports
Merge pull request #170 from akvo/issue/160-uppercase

[#160] Revert all-caps policy
[#171] Bump version number
[#171] Update release notes
Merge pull request #172 from akvo/release/2.0.3

Release/2.0.3
Merge branch 'develop'
[#173] Only accept 200 or 201 responses
[#173] Double check the ETag response header
[#173] Bump version (hotfix)
[#173] Update release notes
[#173] Use a more accurate log message
Merge pull request #174 from akvo/hotfix/173-s3-put

Hotfix/173 s3 put