bnd: Add missing line continuation char to Bundle-Description

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
gradle: Trim default value if string

For consistency with the bndUnprocessed method, we also trim the supplied
defaultValue, if it is a string.

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
gradle: Remove default values for properties with bnd defined defaults

Fixes #579

Signed-off-by: BJ Hargrave <bj@bjhargrave.com>
Merge pull request #584 from bjhargrave/issue579

gradle: Remove default values for properties with bnd defined defaults