File re-organization. New Makefile.

- Re-organized source code files into a ‘grbl’ directory to lessen one
step in compiling Grbl through the Arduino IDE.

- Added an ‘examples’ directory with an upload .INO sketch to further
simplify compiling and uploading Grbl via the Arduino IDE.

- Updated the Makefile with regard to the source code no longer being
in the root directory. All files generated by compiling is placed in a
separate ‘build’ directory to keep things tidy. The makefile should
operate in the same way as it did before.

limits.h

@@ -1,41 +0,0 @@
-/*
-  limits.h - code pertaining to limit-switches and performing the homing cycle
-  Part of Grbl v0.9
-
-  Copyright (c) 2012-2015 Sungeun K. Jeon  
-
-  Grbl is free software: you can redistribute it and/or modify
-  it under the terms of the GNU General Public License as published by
-  the Free Software Foundation, either version 3 of the License, or
-  (at your option) any later version.
-
-  Grbl is distributed in the hope that it will be useful,
-  but WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-  GNU General Public License for more details.
-
-  You should have received a copy of the GNU General Public License
-  along with Grbl.  If not, see <http://www.gnu.org/licenses/>.
-*/
-/* 
-  This file is based on work from Grbl v0.8, distributed under the 
-  terms of the MIT-license. See COPYING for more details.  
-    Copyright (c) 2009-2011 Simen Svale Skogsrud
-*/  
-
-#ifndef limits_h
-#define limits_h 
-
-
-// Initialize the limits module
-void limits_init();
-
-void limits_disable();
-
-// Perform one portion of the homing cycle based on the input settings.
-void limits_go_home(uint8_t cycle_mask);
-
-// Check for soft limit violations
-void limits_soft_check(float *target);
-
-#endif