EN_openX allows an EPANET input file to be opened even if it has errors. This required re-arranging code, mainly in input3.c, so that default values are assigned to an object before its input line is parsed.
The existing EN_setstatusreport function only allows one to set the level of status reporting and not retrieve this value. A new EN_STATUS_REPORT constant was added, to be used with EN_setoption and EN_getoption, to provide read/write access to the level of status reporting.
Fixes possible seg fault condition in EN_getrule. Also defines EN_MISSING as an API constant since it can be assigned internally to several variables that are retrievable by the API.
