fix(pager): use relative units for button metrics (#267)

scss/pager/_theme.scss

@@ -1,4 +1,7 @@
 @include exports("pager/theme") {
+    $pager-form-line-height-em: $form-line-height * 1em !default;
+    $pager-button-padding-y: .5em !default;
+    $pager-buttons-size: calc(#{$pager-form-line-height-em} + 2px) !default; /// icon button size + 2px border (top and bottom)
 
     // Theme
     .k-pager-wrap {
@@ -36,6 +39,14 @@
             @include border-radius( $border-radius );
         }
 
+        .k-link,
+        .k-state-selected {
+            padding: $pager-button-padding-y;
+            width: $pager-buttons-size;
+            height: $pager-buttons-size;
+            line-height: $pager-buttons-size;
+        }
+
     }
     .k-pager-numbers {