[j2x] Added a possibility to convert statements

Change-Id: Ibda7e667e03e303244e877a9cc985065f85050ce
[imports] fixed NPE during collecting imports from implicit receiver

Change-Id: Id27639fadaefb7fa1d14a23405bbf78bca626685
Merge "[j2x] Added a possibility to convert statements"
Merge "[imports] fixed NPE during collecting imports from implicit receiver"