Implement kerning, ligatures, etc., and cleanup; in ios.

Implement hasGlyph ligature helper.

Export view property setters for:
 text: textLength, baselineShift, lengthAdjust, alignmentBaseline,
 textPath: side, method, midLine, spacing.

Attempt to fix alignmentBaseline and baselineShift,
but both properties are nil at all times, I must be missing something.

ios/Elements/RNSVGGroup.h

@@ -13,7 +13,6 @@
 #import "RNSVGSvgView.h"
 #import "RNSVGPath.h"
 #import "GlyphContext.h"
-#import "RNSVGGlyphContext.h"
 
 @interface RNSVGGroup : RNSVGPath <RNSVGContainer>
 
@@ -22,7 +21,6 @@
 - (void)renderPathTo:(CGContextRef)context;
 - (void)renderGroupTo:(CGContextRef)context;
 
-- (RNSVGGlyphContext *)getRNSVGGlyphContext;
 - (GlyphContext *)getGlyphContext;
 - (void)pushGlyphContext;
 - (void)popGlyphContext;

ios/Elements/RNSVGGroup.m

@@ -11,7 +11,6 @@
 @implementation RNSVGGroup
 {
     GlyphContext *_glyphContext;
-    RNSVGGlyphContext *_RNSVGGlyphContext;
 }
 
 - (void)renderLayerTo:(CGContextRef)context
@@ -52,17 +51,10 @@
     CGFloat width = CGRectGetWidth(clipBounds);
     CGFloat height = CGRectGetHeight(clipBounds);
 
-    _RNSVGGlyphContext = [[RNSVGGlyphContext alloc] initWithDimensions:width
-                                                           height:height];
     _glyphContext = [[GlyphContext alloc] initWithScale:1 width:width
                                                            height:height];
 }
 
-- (RNSVGGlyphContext *)getRNSVGGlyphContext
-{
-    return _RNSVGGlyphContext;
-}
-
 - (GlyphContext *)getGlyphContext
 {
     return _glyphContext;
@@ -70,13 +62,11 @@
 
 - (void)pushGlyphContext
 {
-    //[[[self getTextRoot] getRNSVGGlyphContext] pushContext:self.font];
     [[[self getTextRoot] getGlyphContext] pushContextWithRNSVGGroup:self font:self.font];
 }
 
 - (void)popGlyphContext
 {
-    //[[[self getTextRoot] getRNSVGGlyphContext] popContext];
     [[[self getTextRoot] getGlyphContext] popContext];
 }