Convert tests to tcltest and integrate into Travis (#5)

* convert some tests to tcltest

* exit with non-zero value if any test fails

tests/version.test

@@ -0,0 +1,11 @@
+package require TclCurl
+package require tcltest
+namespace import ::tcltest::*
+
+test 1.01 {: Test that curl::version returns something} -body {
+	set result [curl::version]
+
+	return $result
+} -match regexp -result {^TclCurl Version \d+\.\d+\.\d+ \(libcurl/\d+\.\d+\.\d+ .*?\)$}
+
+cleanupTests