Update: Readme and Environment

Author: Shunichi09

.travis.yml

@@ -8,7 +8,7 @@ install:
   - pip install coveralls
 
 script:
-  - coverage run --source=PythonLinearNonlinearControl setup.py test
+  - coverage run --source=PythonLinearNonlinearControl setup.py pytest
 
 after_success:
   - coveralls

Environments.md

@@ -7,7 +7,7 @@
 | Two wheeled System (Moving Goal) (Coming soon) | x | ✓ | 3 | 2 | 
 | Cartpole (Swing up) | x | ✓ | 4 | 1 | 
 
-## FistOrderLagEnv
+## [FistOrderLagEnv](PythonLinearNonlinearControl/envs/first_order_lag.py)
 
 ### System equation.
 
@@ -24,7 +24,7 @@ R = diag[1., 1.]
 
 X_g denote the goal states.
 
-## TwoWheeledEnv
+## [TwoWheeledEnv](PythonLinearNonlinearControl/envs/two_wheeled.py)
 
 ### System equation.
 
@@ -39,7 +39,7 @@ R = diag[0.1, 0.1]
 
 X_g denote the goal states.
 
-## CatpoleEnv (Swing up)
+## [CatpoleEnv (Swing up)]((PythonLinearNonlinearControl/envs/cartpole.py))
 
 System equation.