#72 Fixed memory leak

[AlecHaring]

Fixed memory leak detailed in issue #72.

Added a new wrapper class named value_array for SCITER_VALUE arrays. It makes it so we can keep track of them throughout their entire lifecycle and clear them from memory once they no longer are in use.

It also simplifies how you interact with them. Instead of:

sciter_array = (SCITER_VALUE * 5)()
sv = sciter.Value(value)
sv.copy_to(sciter_array[0])

you can just do:

sciter_array = value_array(length=5)
sciter_array[0] = value