fix(button): Changed button corner radius from 3px to 2px (#1441)

Author: chouclee

src/lib/button-toggle/button-toggle.scss

@@ -3,7 +3,7 @@
 
 $md-button-toggle-padding: 0 16px !default;
 $md-button-toggle-line-height: 36px !default;
-$md-button-toggle-border-radius: 3px !default;
+$md-button-toggle-border-radius: 2px !default;
 
 md-button-toggle-group {
   @include md-elevation(2);

src/lib/button/_button-base.scss

@@ -26,7 +26,7 @@ $md-button-padding: 0 16px !default;
 $md-button-min-width: 88px !default;
 $md-button-margin: 0 !default;
 $md-button-line-height: 36px !default;
-$md-button-border-radius: 3px !default;
+$md-button-border-radius: 2px !default;
 
 // Icon Button standards
 $md-icon-button-size: 40px !default;