Changes to vector expression templates

Major changes:

• Added vector functions equalTo, notEqualTo, less, lessEqual, greater, greaterEqual
• Changed logicalAnd, logicalOr, binaryAnd, binaryOr, binaryXor from vertical to horizontal expressions
• Added vertical operations all and any
• Renamed binary vector expressions min, max to minimum, maximum
• Removed operators <, <=, >, >= for all vector types
• Added back operators <, <=, >, >= for static vectors and expressions – but now they perform lexicographic comparison instead of all(less(a, b)) etc.

See #79 (closed) and #134 (closed) for the motivation behind these changes.

Closes #79 (closed) and #134 (closed).