Dropped rxjs-compat dependency

Tagged version 4.2.0

Support v5

feat: add isValid((prop | *), [conditions]) method

fix(ngxerror.directive): Array.includes not support in IE, switch to …

…indexOf

chore(readme): add new docs for hasError(‘*’)

chore(readme): add new docs for hasError conditions

chore(readme): add new APIs

Merge pull request #3 from markgoho/patch-1

Add "error reporting" to description

chore(circle): fix circleci build