sw: make these public as well for unit tests

All are Sw-prefixed or are in Sw-prefixed namespace, so what can go
wrong.

Change-Id: Icbd8cead5e1db88d34519b09b21e64735ccb2734
CppunitTest_sw_uiwriter: add testcase for ExportRTF()

Change-Id: I49a86e6a5cd525118d902b37825cfdb7dc8e70d2