XD-632: Add --file & --contentType support to http post command
* Add support for file to http post + enhance http source to honor Content-Type if present
* Use ISO-8859-1 as the default charset
XD-648 Regression test on file source

fix dir attribute of file source

rename duplicate parameter

add basic tests against file source/sink

remove fromEnd
XD-655 - Trimmed http post command output
XD-650 Ensure a clean build after running gradle->refresh
XD-660 - Renamed XD shell scripts to xd-shell
XD-635: Updated all polling sources to use fixed-delay and fixedDelay property
XD-561 Parse now verifies that all modules are valid.

XD-561 Tests now support enhanced parser

Merged code after rebase.

Added changes requested from code review.

EnhancedParser now checks for nulls in its constructors.

Code Meets Code Review requests.

XD-561B Added Property checks for modules.

Code checks JDBC, file, hdfs and gemfire module definition properties.