Feature request: daemon support

[SRomansky]

Hi, does SourcererCC have any support for running as a daemon?
For example, SCC is launched as a background process after loading the dataset. The daemon can then be given queries and detect clones in the query without reloading the dataset. The resulting clones are then sent back to whomever initialized the query.

[SRomansky]

ae2a835
The branch and commit above have support for daemonizing SourcererCC.
./runnodes daemon 1

It loads the dataset from the properties file when you start it normally.
When you send a post to localhost:4567/query the daemon will load the
data from the QUERY_DIR_PATH in the properties file. The daemon will
then query that dataset against the previously loaded dataset.
The data in QUERY_DIR_PATH can be replaced and a new POST can be
send to the URL to run a new query.

The branch also includes a Dockerfile which can build a copy of SourcererCC. There is also a script to mount host directories in the docker container, so it is possible to mount the query/dataset/outputset folders into the container and run the jar on them.

The branch also includes a gradle.build file to make the indexbased.SearchManager.jar. The gradle file doesn't contain all of the commands the ant xml file has. But, there is support in gradle to load all of the commands from the ant file.