Map name of property

Allow a property copied to the build.properties to be mapped to another name.

Suppose the property is specified in the settings.xml:
<properties>
<property>
<name>bugzillaUser</name>
<mappedName>build.bugzilla.user</mappedName>
</property>
</properties>
The value of @bugzillaUser@ is copied to the build.properties with name @build.bugzilla.user@.