Updated docs to v1.7.4 

Updated docs 

Merge pull request robotframework#457 from rtomac/1.7.2-release Prepare for 1.7.2 release

Prepare for 1.7.1 release 

Merge pull request robotframework#425 from zephraph/1.7-release Update docs for 1.7 release

1.6.0 release 

1.5.0 release 

1.4.0 release 

1.3.0 release 

1.2.0 release