Removed double "=" on JAVA_HEAP parameter.

With a double "=", the max heap argument passed to the JVM will be -Xmx=1024m
instead of -Xmx1024m, which is invalid.

Also fixed help message, default heap is 1024 Mb and not 1024 kb.
Merge pull request #135 from gehel/1.6-wip

Removed double "=" on JAVA_HEAP parameter.