fix LogicalVector construction from bool
alternate strategy
alternate LogicalVector construction from bool

without using default template arguments, which is a C++11 feature.

The handcrafted traits::is_bool may not cover all cases, but it works well for
the constructor.
Merge pull request #194 from luckyrandom/feature/logical-vector-from-bool

alternate LogicalVector construction from bool
Merge branch 'master' into feature/logical-vector-from-bool

Conflicts:
	ChangeLog
Merge pull request #204 from RcppCore/feature/logical-vector-from-bool

Feature/logical vector from bool