More README

gdb-port/README

+Requirements
+
+- Hammer and the target parser (pdf, for now) must be built with debug symbols for the tool to work
+- The GUI component uses Tkinter to draw a window
+
 Invocation
 
 ```
@@ -18,11 +23,11 @@ Tests
 gdb -ex "source /path/to/utility-commands.py" -ex "hammer-parse-stop-at-pos 50" -ex "source /path/to/parser-type-instrumentation-gdb.py" -ex "source /path/to/parser-name-instrumentation-gdb.py" -ex "source /path/to/tests/unit/parser-envs-pdf.py" --args /path/to/pdf /path/to/input.pdf
 ```
 
-Commands
+# Commands
 
 The tool is in an experimental stage. The interface is liable to change.
 
-Execution control:
+## Execution control
 
 ```
 hammer-parse-stop-at-input-pos <number>
@@ -59,7 +64,7 @@ hammer-parse-continue
 
 Alias of GDB `continue`. May change later.
 
-Querying:
+## Querying
 
 ```
 hammer-parser-backtrace [number]