Paste indent normalization works with on lines w/ mixed indentation

Normalizing the indent no longer explodes when pasting on a line that has mixed tabs and spaces when the edit session is using hard tabs.

src/app/edit-session.coffee

@@ -124,10 +124,13 @@ class EditSession
     @buffer.change([[bufferRow, 0], [bufferRow, currentIndentString.length]], newIndentString)
 
   indentLevelForLine: (line) ->
-    if line.match(/^\t/)
-      line.match(/^\t*/)?[0].length
+    if match = line.match(/^[\t ]+/)
+      leadingWhitespace = match[0]
+      tabCount = leadingWhitespace.match(/\t/g)?.length ? 0
+      spaceCount = leadingWhitespace.match(/[ ]/g)?.length ? 0
+      tabCount + (spaceCount / @getTabLength())
     else
-      line.match(/^\s*/)?[0].length / @getTabLength()
+      0
 
   buildIndentString: (number) ->
     if @softTabs

src/app/selection.coffee

@@ -238,11 +238,9 @@ class Selection
 
   adjustIndentationForLine: (line, delta) ->
     currentIndentLevel = @editSession.indentLevelForLine(line)
-    currentIndentString = @editSession.buildIndentString(currentIndentLevel)
     desiredIndentLevel = Math.max(0, currentIndentLevel + delta)
     desiredIndentString = @editSession.buildIndentString(desiredIndentLevel)
-
-    line.replace(new RegExp("^#{currentIndentString}"), desiredIndentString)
+    line.replace(/^[\t ]*/, desiredIndentString)
 
   backspace: ->
     if @isEmpty() and not @editSession.isFoldedAtScreenRow(@cursor.getScreenRow())