Try to be a little more consistent: all parameters are final

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Fix check style warning

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Added SOM standard library from common repository, removed embedded version

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Restored directory structure by adding symlinks

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Added new tests from the standard library

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Implemented System>>#fullGC

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Use 1-based indexes for substring primitive

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Added Integer class>>#fromString: and fixed sqrt primitive to return integers when possible

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Added Double>>#round

Signed-off-by: Stefan Marr <git@stefan-marr.de>
Changed code to use Truffles new DefaultSourceSection

Signed-off-by: Stefan Marr <git@stefan-marr.de>