2.0 Update

**Breaking Changes**  
* Deprecated some delegate methods and replaced with newer delegate methods with more parameters.  
* Made some properties private.  

**New Features**  
 * New delegate methods to specify line color and alpha.  
 * New delegate methods that notify the delegate when the graph starts and ends updates.  
 * Added new calculation methods to calculate the graph's sum, average, standard deviation, median, mode, and more. 
 * Added a new graph snapshot method which efficiently captures a UIImage of the graph.  
 * Updated Sample App to reflect new features and changes.  
 * Added pre-compiler check for the Objective-C Module Build Setting. Modules are used if enabled, otherwise traditional imports are used.  
 * Added a warning for projects without ARC.

**Fixed Issues**  
 * Added call to super in layoutSubviews.  
 * The reloadGraph method now calls setNeedsLayout instead of directly calling layoutSubviews.
 * Improved memory performance with @autoreleasepool blocks.  
 * Added Type-Safety for 64-bit architecture.  
 * Fixed X-Axis layout issues.  
 * Fixed typos.