Separated State code into header and cpp files

Updated library.properties version...

From @Voha888 :

When creating a project in VScode with the Platformio plugin, it becomes necessary to re-include the library header file in several files, for example, to use the extern keyword.
The original version of the library does not allow this. I separated the class methods into .cpp files, now the library header files can be included in several compilation units.

Separated State code into header and cpp files

From @Voha888 :

When creating a project in VScode with the Platformio plugin, it becomes necessary to re-include the library header file in several files, for example, to use the extern keyword.
The original version of the library does not allow this. I separated the class methods into .cpp files, now the library header files can be included in several compilation units.

Improvements to remove compiler warnings

Improvements submitted by @smartynov.

Set executeOnce when transitionTo is used to force a transition.

v1.0.11

Merge branch 'master' of https://github.com/jrullan/StateMachine

Fixed problem with executeOnce under certain conditions.

v1.0.10

Update README.md

Updated sample sketch.

v1.0.9

Updated example sketch

Execute once per state attribute and setTransition

Added mechanism that lets you execute state logic's code once using the value of the state machine's attribute executeOnce. Also implemented a new method to set a transition's target using setTranstion.

Removed DEBUG for compatibility with other libraries.

v1.0.6

Removed DEBUG to avoid conflict with another library.

States are aware of their index, for future functionality.

v1.0.5

Made states aware of their index in the states List

Updated version number to match release number

v1.0.4

Update library.properties