Eval functions: encode functions

- URL_encode()
- XML_encode()
- CRC32_checksum()
Merge branch 'master' into 5-josm-eval-functions

Conflicts:
	CHANGELOG.creole
Eval: inline condition operator condition?if_true:else

- fixes #39
Parse/Compile Eval: differenciate between ary/unary operators
Eval: function neg(), unary negation: -fun()
Eval: equal: also accept '=' as operator
Eval: identifiers may contain #
Eval: functions red(), green(), blue(), alpha()
Eval: rename lefthandtraffic() to is_left_hand_traffic() (and right* too)
Eval: new functions regexp_test() and regexp_match()
Eval: restructure documentation
Eval: fix documentation
Eval: fix typo in documenation
Eval: new functions floor(), ceil()
Eval: min(), max() no longer accept input with units
Eval: new function length()
Eval: str(): bugfix, add tests
Stat: stat_properties() accept params pseudo_element, max_prop_id
Eval: new functions has_tag_key(), is_prop_set()
Merge branch 'master' into 5-josm-eval-functions