Clear input when we are adjusting frame

This resolves issue venmo#76
When we are laying out subviews, we were already passing NO for adjustFrame.
When we are reloading data, we were already passing YES for adjustFrame.

It turns out that when we are not adjustingFrame, we do not want to clear the user-entered text, so reuse this boolean to keep from clearing the user text.

VENTokenField/VENTokenField.m

@@ -212,7 +212,7 @@ - (void)layoutTokensAndInputWithFrameAdjustment:(BOOL)shouldAdjustFrame
 
     [self layoutToLabelInView:self.scrollView origin:CGPointZero currentX:&currentX];
     [self layoutTokensWithCurrentX:&currentX currentY:&currentY];
-    [self layoutInputTextFieldWithCurrentX:&currentX currentY:&currentY];
+    [self layoutInputTextFieldWithCurrentX:&currentX currentY:&currentY clearInput:shouldAdjustFrame];
 
     if (shouldAdjustFrame) {
         [self adjustHeightForCurrentY:currentY];
@@ -248,7 +248,7 @@ - (void)layoutScrollView
     [self addSubview:self.scrollView];
 }
 
-- (void)layoutInputTextFieldWithCurrentX:(CGFloat *)currentX currentY:(CGFloat *)currentY
+- (void)layoutInputTextFieldWithCurrentX:(CGFloat *)currentX currentY:(CGFloat *)currentY clearInput:(BOOL)clearInput
 {
     CGFloat inputTextFieldWidth = self.scrollView.contentSize.width - *currentX;
     if (inputTextFieldWidth < self.minInputWidth) {
@@ -258,7 +258,9 @@ - (void)layoutInputTextFieldWithCurrentX:(CGFloat *)currentX currentY:(CGFloat *
     }
 
     VENBackspaceTextField *inputTextField = self.inputTextField;
-    inputTextField.text = @"";
+    if (clearInput) {
+        inputTextField.text = @"";
+    }
     inputTextField.frame = CGRectMake(*currentX, *currentY + 1, inputTextFieldWidth, [self heightForToken] - 1);
     inputTextField.tintColor = self.colorScheme;
     [self.scrollView addSubview:inputTextField];