Vignesh A

Expose controls on which block, method, relation can be included in uml diagram

2

For my usecase, I need to ignore some portions in the uml diagram whenever i was generating, thought it would be useful for others as well, so raising this PR...

collection_exists throws UnexpectedResponse

3

if i give invalid collection name, i am getting False (expected)  but if i give a empty collection name, it is throwing exception (i am expecting false)  same...

1) Added instruction to create virtual env 2) Fixed typo in installation command `-t` -> `-r`