RTSD-79, add readme.md

tools/readme.md

+# VHDL STYLE FIX
+
+Style fixing done:
+
+- Remove trailing spaces.
+- Add spaces around operators.
+- StandardLogic to lowercase.
+- Constants to lowercase.
+- Keywords to lowercase.
+- Types to lowercase.
+- Type Conversions to lowercase.
+- Resolutions to lowercase.
+- Attributes to lowercase.
+- Remove space between type function and bracket. 
+
+## Usage:
+
+run fix on all vhdl files:
+
+```
+cd git/hdl
+. ./init_hdl.sh
+./vhdl_style_fix_all_files.py -p 4
+```
+
+## Todo:
+
+- Align all code.
+- Check if tabs are converted to spaces.
+- Remove spaces between all type of functions and open bracked.
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