Document CLI tools debian quick install

[clach04]

Command Line Tools can be used with pre-built dependencies.

[clach04]

NOTE on my SBC the Linux distro version of PIL is 4.0.0 - so if WebP support is not needed, need to disable Pillow 5 check.

I don't think that's worth documenting in the readme but mentioning for completeness. See #366

[localhost:~/kcc] # git diff
diff --git a/kindlecomicconverter/shared.py b/kindlecomicconverter/shared.py
index 507873b..1435a42 100644
--- a/kindlecomicconverter/shared.py
+++ b/kindlecomicconverter/shared.py
@@ -124,7 +124,8 @@ def dependencyCheck(level):
             missing.append('python-slugify 1.2.1+')
     try:
         from PIL import __version__ as pillowVersion
-        if StrictVersion('5.2.0') > StrictVersion(pillowVersion):
+        #if StrictVersion('5.2.0') > StrictVersion(pillowVersion):
+        if StrictVersion('4.0.0') > StrictVersion(pillowVersion):
             missing.append('Pillow 5.2.0+')
     except ImportError:
         missing.append('Pillow 5.2.0+')

[clach04]

For more complete diff/commit to revert PIL/Pillow version check see clach04@590a93d

[darodi]

@clach04
thanks
merged in v5.6.1