PEP8 improvements white space here and there

I search with regexp ",[^\s-]" to spot missing space after comma. I also, add double break line in front of function or class. I change a couple of comparator in order to add space in front and after " == " for instance.

gluon/sqlhtml.py

@@ -45,9 +45,11 @@ except ImportError:
 
 widget_class = re.compile('^\w*')
 
+
 def add_class(a, b):
     return a+' '+b if a else b
 
+
 def represent(field, value, record):
     f = field.represent
     if not callable(f):
@@ -191,9 +193,11 @@ class TimeWidget(StringWidget):
 class DateWidget(StringWidget):
     _class = 'date'
 
+
 class DatetimeWidget(StringWidget):
     _class = 'datetime'
 
+
 class TextWidget(FormWidget):
     _class = 'text'
 
@@ -209,6 +213,7 @@ class TextWidget(FormWidget):
         attr = cls._attributes(field, default, **attributes)
         return TEXTAREA(**attr)
 
+
 class JSONWidget(FormWidget):
     _class = 'json'
 
@@ -226,6 +231,7 @@ class JSONWidget(FormWidget):
         attr = cls._attributes(field, default, **attributes)
         return TEXTAREA(**attr)
 
+
 class BooleanWidget(FormWidget):
     _class = 'boolean'
 
@@ -814,6 +820,7 @@ def formstyle_bootstrap(form, fields):
             parent.append(DIV(label, _controls, _class='control-group', _id=id))
     return parent
 
+
 def formstyle_bootstrap3(form, fields):
     """ bootstrap 3 format form layout
 
@@ -1812,7 +1819,6 @@ class SQLFORM(FORM):
         return CAT(
             DIV(_id=panel_id, _style="display:none;", *criteria), fadd)
 
-
     @staticmethod
     def grid(query,
              fields=None,
@@ -2708,6 +2714,7 @@ class SQLFORM(FORM):
             constraints = {}
         field = None
         name = None
+
         def format(table, row):
             if not row:
                 return T('Unknown')
@@ -3167,6 +3174,7 @@ class ExportClass(object):
     def export(self):
         raise NotImplementedError
 
+
 class ExporterTSV(ExportClass):
     label = 'TSV'
     file_ext = "csv"
@@ -3203,6 +3211,7 @@ class ExporterTSV(ExportClass):
             out.truncate(0)
         return str(final.getvalue())
 
+
 class ExporterCSV(ExportClass):
     #CSV, represent == True
     label = 'CSV'
@@ -3220,6 +3229,7 @@ class ExporterCSV(ExportClass):
         else:
             return None
 
+
 class ExporterCSV_hidden(ExportClass):
     #pure csv, no represent.
     label = 'CSV'
@@ -3235,6 +3245,7 @@ class ExporterCSV_hidden(ExportClass):
         else:
             return ''
 
+
 class ExporterHTML(ExportClass):
     label = 'HTML'
     file_ext = "html"
@@ -3247,6 +3258,7 @@ class ExporterHTML(ExportClass):
         xml = self.rows.xml() if self.rows else ''
         return '<html>\n<head>\n<meta http-equiv="content-type" content="text/html; charset=UTF-8" />\n</head>\n<body>\n%s\n</body>\n</html>' % (xml or '')
 
+
 class ExporterXML(ExportClass):
     label = 'XML'
     file_ext = "xml"
@@ -3261,6 +3273,7 @@ class ExporterXML(ExportClass):
         else:
             return '<rows></rows>'
 
+
 class ExporterJSON(ExportClass):
     label = 'JSON'
     file_ext = "json"