fix(filters): default filters are purple

This commit makes the default filters purple to increase legibility.
The previous version had poor contrast for users without proper eye
equipment - yellow on white.  Here we use a dark purple to increase
contrast and aid readability.

Closes #1949.

client/src/less/bhima-bootstrap.less

@@ -14,6 +14,8 @@
 @ima-light-orange:    #fdba64;
 @ima-light-blue:      #6fbdee;
 
+@ima-purple : #7859BF;
+
 /** @todo move all structure code into less with configurable variables */ /** * Application structure variables - these widths are used to determine how much
  * space the tree navigation takes up in its `expanded` and `collapsed` states.
  */
@@ -124,6 +126,11 @@ input[type=number] {-moz-appearance: textfield;}
   padding-bottom : @grid-gutter-width / 2;
 }
 
+.label.label-emphasize{
+  background-color: @ima-purple;
+  color: #fff;
+}
+
 /* expert mode */
 /* @padding-base-vertical: 3px; */
 /* @padding-base-horizontal: 6px; */

client/src/modules/templates/bhFilters.tmpl.html

@@ -7,7 +7,7 @@
     <!--
       TODO: these should be a custom CSS class.  Label is just too small!
     -->
-    <span class="label label-warning">
+    <span class="label label-emphasize">
       <i class="fa fa-filter"></i>
       <span translate>{{filter._label}}</span> {{ filter._comparitor ? " " + filter._comparitor : ":" }}
       {{ filter.displayValue }}