Adds Linux HLS build scripts

This adds an equivalent to the `Command.bat` for Windows, generated by
net.sf.orcc.backends/src/net/sf/orcc/backends/c/hls/BatchCommandPrinter.xtend

See orcc/orcc#120 for details.
Documents Linux and Windows HLS scripts

The Linux HLS build scripts from
d4197b6f96e4e2d357acfc602ceab0ccd2934828 are documented with
information on setting the $PATH and $XILINXD_LICENSE_FILE environment
variables.

The existing Windows HLS build scripts are documented with information
on setting the $PATH $AUTOESL_HOME and $VIVADO_HLS_HOME environment
variables. The `mabid` user specific directory paths are removed.

Relates to orcc/orcc#120
Merge pull request #123 from robstewart57/hls-scripts-pull-request

HLS build scripts pull request