RPC raises errorCB when result is empty

- If service result is empty, it returns errorCB
- RPC can now raise errorCB if defined

Jira Issue: WP-1221
Merge pull request #45 from habibvirji/WP-1221-pzhFunctionalityFixes

RPC raises errorCB when result is empty
fixes regexpr on testing appId

Jira-issue: WP-1243
Merge pull request #46 from mlasak/WP-1243

fixes regexpr on testing appId
Removed constraints on strings length

Jira-issue: WP-1249
Merge pull request #48 from ccameroni/WP-1249-fix-JSONRPC-message-validation

WP-1249 Fixed JSONRPC message validation