Move past the commodity sign
Remove reference to depricated ! operator in Chapt 4
Merge pull request #209 from wcravens/fix_block_comment_instructions_chapt_4

Remove reference to depricated ! operator in Chapt 4
Find first numeral or minus sign, instead of blind move
Merge pull request #208 from vkurup/master

ledger-copy-transaction-at-point: leave point in better place for editing
Remove some obsolete material from the build instructions.

It no longer works to create the "build" directory and then build
separate optimized and debug versions.  As confirmed in IRC with sm
and egh, the former instructions resulted in an error:

  $ mkdir build
  $ ./acprep opt make
  make: *** No targets specified and no makefile found.  Stop.
  acprep: ERROR: Execution failed: make
  $ ./acprep debug make
  make: *** No targets specified and no makefile found.  Stop.
  acprep: ERROR: Execution failed: make

Maybe there's a fix for this, but I don't know what it is, so this
commit just makes the build instructions work for the common case.
Merge pull request #210 from OpenTechStrategies/fix-build-instructions

Remove some obsolete material from the build instructions.
Guard against a possible null value