[INTERNAL] sap.ui.model.odata.type.*: optimization

PS1: getName()
PS2: don't store default constraints
PS3: isNullable


Change-Id: I150daaeb33c51d810f4544936a00eac166515f7d
JIRA: FLPUISERVICES2014-1085
Merge "[INTERNAL] sap.ui.model.odata.type.*: optimization"