Avoid "DeprecationWarning: invalid escape sequence"

Without this change, many warnings like this will be generated while running pytest:
```
test/test_template.py:3
  /build/source/test/test_template.py:3: DeprecationWarning: invalid escape sequence '\/'
    """!
```
This can also be seen when manually running python with warnings enabled.

This happens because the comment uses a multiline string and Python interprets the backslash in the logo as an escape character and complains that \/ is not a valid escape sequence. To fix this, prepend the string with the letter r to indicate that the backslash should be treated as a literal character, see https://docs.python.org/3/reference/lexical_analysis.html#index-20.
I also applied this change to all the comment strings since that shouldn't break anything and to establish it as a pattern for the future so this problem hopefully never happens again.

This is what I did specifically:
- Change the comment at the top of bw_client.py and bw_server.py to start with `"""!` since that seems to be the pattern here
- Search-and-Replace all occurances of `"""!` with `r"""!`
- Manually change the strings in `logoToLog()` in boswatch/utils/header.py

test/module/test_descriptor.py

@@ -1,6 +1,6 @@
 #!/usr/bin/python
 # -*- coding: utf-8 -*-
-"""!
+r"""!
     ____  ____  ______       __      __       __       _____
    / __ )/ __ \/ ___/ |     / /___ _/ /______/ /_     |__  /
   / __  / / / /\__ \| | /| / / __ `/ __/ ___/ __ \     /_ <
@@ -31,7 +31,7 @@ def setup_method(method):
 
 @pytest.fixture
 def makeDescriptor():
-    """!Build a descriptor object with loaded configuration"""
+    r"""!Build a descriptor object with loaded configuration"""
     config = ConfigYAML()
     assert config.loadConfigFile(paths.TEST_PATH + "test_config.yaml") is True
     descriptor = Descriptor(config.get("descriptor_test"))
@@ -40,33 +40,33 @@ def makeDescriptor():
 
 @pytest.fixture
 def makePacket():
-    """!Build a BW Packet object"""
+    r"""!Build a BW Packet object"""
     packet = Packet()
     return packet
 
 
 def test_descriptorFoundFirst(makeDescriptor, makePacket):
-    """!Run descriptor on the first entry in list"""
+    r"""!Run descriptor on the first entry in list"""
     makePacket.set("tone", "12345")
     makePacket = makeDescriptor.doWork(makePacket)
     assert makePacket.get("description") == "Test 12345"
 
 
 def test_descriptorFoundSecond(makeDescriptor, makePacket):
-    """!Run descriptor on the second entry in list"""
+    r"""!Run descriptor on the second entry in list"""
     makePacket.set("tone", "23456")
     makePacket = makeDescriptor.doWork(makePacket)
     assert makePacket.get("description") == "Test 23456"
 
 
 def test_descriptorNotFound(makeDescriptor, makePacket):
-    """!Run descriptor no matching data found"""
+    r"""!Run descriptor no matching data found"""
     makePacket.set("tone", "99999")
     makePacket = makeDescriptor.doWork(makePacket)
     assert makePacket.get("description") == "99999"
 
 
 def test_descriptorScanFieldNotAvailable(makeDescriptor, makePacket):
-    """!Run descriptor on a non existent scanField"""
+    r"""!Run descriptor on a non existent scanField"""
     makePacket = makeDescriptor.doWork(makePacket)
     assert makePacket.get("description") is None