fix CR-IC-97 (indent is counted in tab units so need multiplication instead of division)

handle empty insertion line properly

python/testData/copyPaste/IndentTabIncrease.after.py

@@ -0,0 +1,6 @@
+print "Line 2"
+class Test:
+	def __init__(self):
+		print "Line 2"
+
+		print "Line 1"

python/testData/copyPaste/IndentTabIncrease.dst.py

@@ -0,0 +1,5 @@
+print "Line 2"
+class Test:
+	def __init__(self):
+		<caret>
+		print "Line 1"

python/testData/copyPaste/IndentTabIncrease.src.py

@@ -0,0 +1,5 @@
+<selection>print "Line 2"
+</selection><caret>
+class Test:
+	def __init__(self):
+		print "Line 1"

python/testSrc/com/jetbrains/python/PyCopyPasteTest.java

@@ -270,6 +270,10 @@ public class PyCopyPasteTest extends PyTestCase {
   }
 
   public void testIndentTab() {
+    doTestTabs();
+  }
+
+  private void doTestTabs() {
     final CommonCodeStyleSettings.IndentOptions indentOptions =
       CodeStyleSettingsManager.getSettings(myFixture.getProject())
         .getIndentOptions(PythonFileType.INSTANCE);
@@ -282,6 +286,10 @@ public class PyCopyPasteTest extends PyTestCase {
     }
   }
 
+  public void testIndentTabIncrease() {
+    doTestTabs();
+  }
+
   private void doTest() {
     String name = getTestName(false);