Ignore .idea/ and delete from repository

[re #10338]
Remove usages of $params['elem'], remove unused code

[re #10338]
Fix docblocks

[re #10338]
Replace declaration of blocks to the .xml file
Fix validation messages

[re #10338]
Remove unused method from preorder collection model

[re #10338]
Remove unused code & usages of $param['elem']

[re #10338]
Merge pull request #19 from pavdan/oneclickorder

Oneclickorder