add option help for loadjson, use FastArrayParser to specify parser level

git-svn-id: http://svn.code.sf.net/p/iso2mesh/code/trunk/jsonlab@448 786e58fb-9377-0410-9ff7-e4ac0ac0635c
output compact JSON in savejson

git-svn-id: http://svn.code.sf.net/p/iso2mesh/code/trunk/jsonlab@449 786e58fb-9377-0410-9ff7-e4ac0ac0635c