Skip Python style triple quoted strings

Closes #6.

plugin/sleuth.vim

@@ -13,6 +13,7 @@ function! s:guess(lines) abort
   let heuristics = {'spaces': 0, 'hard': 0, 'soft': 0}
   let ccomment = 0
   let podcomment = 0
+  let triplequote = 0
 
   for line in a:lines
 
@@ -40,6 +41,25 @@ function! s:guess(lines) abort
       continue
     endif
 
+    if line =~# '^=\w'
+      let podcomment = 1
+    endif
+    if podcomment
+      if line =~# '^=\%(end\|cut\)\>'
+        let podcomment = 0
+      endif
+      continue
+    endif
+
+    if triplequote
+      if line =~# '^[^"]*"""[^"]*$'
+        let triplequote = 0
+      endif
+      continue
+    elseif line =~# '^[^"]*"""[^"]*$'
+      let triplequote = 1
+    endif
+
     let softtab = repeat(' ', 8)
     if line =~# '^\t'
       let heuristics.hard += 1