Minor rewordings and links cleanups

Referring to the testing document using an absolute link is necessary to allow
the README to be included via `pdoc`.

README.md

@@ -1,6 +1,8 @@
-# PUMAPY - PPMS Utility Management API Python Interface
+# PUMAPY
 
-Stratocore's PPMS booking system offers an API for fetching information from
+## PPMS Utility Management API - Python Interface
+
+[Stratocore][3]'s *PPMS* booking system offers an API for fetching information from
 the booking system as well as changing its state and properties.
 
 This is a Python 3 package for talking to the so-called *PUMAPI*.
@@ -11,12 +13,13 @@ TODO! Until then you may have a look at the testing instructions.
 
 ## Testing
 
-Automated testing is described in the [TESTING](TESTING.md) document.
+Automated testing is described in the [`TESTING` document on github][2].
 
 ## Note
 
-The PPMS API is not fully clean or consistent. During development of the
-package, we came across several issues (this list is most likely incomplete):
+The PPMS API is not super clean and sometimes quite inconsistent. During
+development of the package, we came across several issues (this list is
+certainly incomplete):
 
 * HTTP status return code is always `200`, even on failed authentication.
 * Results of queries are a mixture of CSV (with headers) and and text with
@@ -35,7 +38,8 @@ package, we came across several issues (this list is most likely incomplete):
   name that is returned e.g. by `getrunningsheet`, making it very hard to
   cross-reference it with data from `getuser`.
 * The result of the `getrunningsheet` query in general is not suited very well
-  for automated processing, it seems to be rather tailored for humans.
+  for automated processing, it seems to be rather tailored for humans and
+  subject to (mis-) interpretation.
 * Unfortunately `Username` and `Systemname` are not the unique id, they are
   rather the full description. Therefore sometimes looping over all users and
   systems is necessary.
@@ -50,3 +54,5 @@ package, we came across several issues (this list is most likely incomplete):
 * [Imagopole PPMS Java client][1]
 
 [1]: https://github.com/imagopole/ppms-http-client/blob/master/src/main/java/org/imagopole/ppms/api/PumapiRequest.java
+[2]: https://github.com/imcf/pumapy/blob/master/TESTING.md
+[3]: https://www.stratocore.com/