fixed the validation of sequences content model when some of the blocks

* xmlregexp.c xmlschemas.c: fixed the validation of sequences
  content model when some of the blocks have min or max, and a couple
  of bugs found in the process.
* result/schemas/list0* test/schemas/list0*: added some specific
  regression tests
Daniel
diff --git a/test/schemas/list0_1.xsd b/test/schemas/list0_1.xsd
new file mode 100644
index 0000000..8966075
--- /dev/null
+++ b/test/schemas/list0_1.xsd
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" elementFormDefault="qualified" attributeFormDefault="unqualified">
+  <xs:element name="test">
+    <xs:annotation>
+      <xs:documentation>Comment describing your root element</xs:documentation>
+    </xs:annotation>
+    <xs:complexType>
+      <xs:sequence>
+        <xs:element name="string" type="xs:string" minOccurs="2" maxOccurs="3"/>
+      </xs:sequence>
+    </xs:complexType>
+  </xs:element>
+</xs:schema>