New congruence relation and abs angle value

[jjdishere]

When discuss the congruence relation of triangles, we do not want to discuss the +- of an angle in many occasion. SAS AAS ASA implies congruence when A is only equality of abs of angle value.

As a solution, we can do:
congruence : \cong = \cong\+ \or \cong\-
orientation-preserving congruence: \cong\+
orientation-reversing congruence: \cong\-

AbsValue of an angle (which is abs of .value.toReal), ang\1.AbsValue = ang\1'.AbsValue if and only if, their value are equal or adds to zero.

With the A in their SAS criterion being
congruence : ang\1.AbsValue = ang\1'.AbsValue (which is abs of .value.toReal)
orientation-preserving congruence: ang\1.value = ang\1'.value
orientation-reversing congruence: ang\1.value = -ang\1.value

[jjdishere]

With new notations \angle_+ \angle_r \angle \measureangle.

With corresponding theorems of \angle_+ , such as AB \perp BC implies\angle_+ A B C = pi/2