Enhanced indentation detection

Now this plugin will handle the following (scary, automatically generated) HTML properly now:

```
<DIV class="mid">
<DIV class="midLt">
<DIV class="midRt">
<DIV id="sectKey-60-cnt" class="midCt">
<DIV class="skDiv">
<DIV class="skBnr ActivityBar">
<DIV>
<TABLE style="WIDTH: 100%; BORDER-COLLAPSE: collapse" cellSpacing="0" cellPadding="0">
<TBODY>
<TR>
<TD class="skBnrLt">
<TABLE style="MARGIN-LEFT: -3px" class="skTbl">
<TBODY>
<TR class="noLn">
<TD style="WIDTH: 99%">
<DIV style="POSITION: relative; FLOAT: left" id="CHARGES" class="skDiv" dropScript="window.navigate('CHARGES-BMOV:' + document.getElementById('CHARGES').value);"><SPAN id="st-CHARGESADD_BUTTON"><A hideFocus onkeydown="ciKD()" id="CHARGESADD_BUTTON" onmouseup="ciUp()" onactivate="ciAct()" class="skBtn" onkeyup="ciKU()" onmousedown="ciDn()" onclick="jscript:window.navigate('CHARGES-ADD_BUTTON:')" href="jscript:void(0)"><B></B><SPAN id="CHARGESADD_BUTTON-icn" class="icn icnAdd"></SPAN><SPAN id="CHARGESADD_BUTTON-cpt">Add a charge</SPAN></A></SPAN></DIV></TD></TR></TBODY></TABLE></TD>
<TD class="skBnrRt" align="right"></TD></TR></TBODY></TABLE></DIV></DIV></DIV></DIV></DIV></DIV></DIV>
<DIV class="btm">
<DIV class="btmLt">
<DIV class="btmRt">
<DIV class="btmCt"><!-- --></DIV></DIV></DIV></DIV></DIV></DIV></DIV>
```

to produce:
```
<DIV class="mid">
    <DIV class="midLt">
      <DIV class="midRt">
        <DIV id="sectKey-60-cnt" class="midCt">
          <DIV class="skDiv">
            <DIV class="skBnr ActivityBar">
              <DIV>
                <TABLE style="WIDTH: 100%; BORDER-COLLAPSE: collapse" cellSpacing="0" cellPadding="0">
                  <TBODY>
                    <TR>
                      <TD class="skBnrLt">
                        <TABLE style="MARGIN-LEFT: -3px" class="skTbl">
                          <TBODY>
                            <TR class="noLn">
                              <TD style="WIDTH: 99%">
                              <DIV style="POSITION: relative; FLOAT: left" id="CHARGES" class="skDiv" dropScript="window.navigate('CHARGES-BMOV:' + document.getElementById('CHARGES').value);"><SPAN id="st-CHARGESADD_BUTTON"><A hideFocus onkeydown="ciKD()" id="CHARGESADD_BUTTON" onmouseup="ciUp()" onactivate="ciAct()" class="skBtn" onkeyup="ciKU()" onmousedown="ciDn()" onclick="jscript:window.navigate('CHARGES-ADD_BUTTON:')" href="jscript:void(0)"><B></B><SPAN id="CHARGESADD_BUTTON-icn" class="icn icnAdd"></SPAN><SPAN id="CHARGESADD_BUTTON-cpt">Add a charge</SPAN></A></SPAN></DIV></TD></TR></TBODY></TABLE></TD>
                    <TD class="skBnrRt" align="right"></TD></TR></TBODY></TABLE></DIV></DIV></DIV></DIV></DIV></DIV></DIV>
  <DIV class="btm">
    <DIV class="btmLt">
      <DIV class="btmRt">
      <DIV class="btmCt"><!-- --></DIV></DIV></DIV></DIV></DIV></DIV></DIV>
```