Update and document compiler to adapt to hledger and Winodws (#149)

Author: Konfekt

compiler/ledger.vim

@@ -32,5 +32,8 @@ if !b:is_hledger
 	CompilerSet errorformat+=%-G%.%#
 	exe 'CompilerSet makeprg='.substitute(g:ledger_bin, ' ', '\\ ', 'g').'\ -f\ ' . substitute(shellescape(expand(g:ledger_main)), ' ', '\\ ', 'g') . '\ '.substitute(g:ledger_extra_options, ' ', '\\ ', 'g').'\ source\ ' . shellescape(expand(g:ledger_main))
 else
-	exe 'CompilerSet makeprg=('.substitute(g:ledger_bin, ' ', '\\ ', 'g').'\ -f\ ' . substitute(shellescape(expand(g:ledger_main)), ' ', '\\ ', 'g') . '\ print\ '.substitute(g:ledger_extra_options, ' ', '\\ ', 'g').'\ >\ /dev/null)'
+	exe 'CompilerSet makeprg='.substitute(g:ledger_bin, ' ', '\\ ', 'g').'\ -f\ ' . substitute(shellescape(expand(g:ledger_main)), ' ', '\\ ', 'g') . '\ check\ '. substitute(g:ledger_extra_options, ' ', '\\ ', 'g')
+	CompilerSet errorformat=%Ehledger:\ %trror:\ %f:%l:%c%.%#:,%-C\ \ \|\\s%#,%-C\%l\ \|%.%#,%-C\ \ \|\\s%#,%-C\ \ \|%p^,%+C%m,%-Z\\s%#
+	" Skip all other lines:
+	CompilerSet errorformat+=%-G%.%#
 endif

doc/ledger.txt

@@ -47,10 +47,14 @@ Tips and useful commands
 	:silent make | redraw! | cwindow
 
   It is recommended to set the value of `g:ledger_extra_options` (see below)
-  as follows:
+  as follows for ledger:
 
         let g:ledger_extra_options = '--pedantic --explicit --check-payees'
 
+  and as follows for hledger:
+
+        let g:ledger_extra_options = '--strict ordereddates payees uniqueleafnames'
+
   to catch most potential problems in your source file.
 
 * Remap vim paragraph motion to move by transaction.