add accessors for game element positions

added functions to get game element positions:
* brick_left, brick_right, brick_top, brick_bottom
* ball_left, ball_right, ball_top, ball_bottom
* player_left, player_right, player_top, player_bottom

using these functions within the calculations of collisions gives
better readability of the algorithms
fix problem with level files too long

when loading files with more than 25 lines, there was memory
allocation done outside bounds, and thus when freeing the memory
of the level not all memory was freed
change header include definitions for every header file

in order to comply with another project standards, the include
definitions have been changed, use of standard as double underscore
before and after filename and replacing dots with underscore
e.g. __GAME_H__ instead of previous _INC_GAME
update code style (blanks lines)

there were many useless blank lines in the code, all have now been removed
fix memory leak when loading level file

a memory leak could occur when loading a level file

the last line of the file was allocating memory for bricks, but if
the line was not ended by a line feed, a new allocation for that line
was performed without freeing the previous one

we need to complete the line and not restart it e.g. keep the row
value and not reset it to 0
re-factor game to remove level from global

level is no more a global variable, but is now included
in the game structure

creation and destruction of level is now done during
game creation and destruction