Redesign @goal_glob

[xonixx]

See #18

New Design

Let's change the behavior to

@goal goal_name @glob *.txt 
 echo $ITEM $INDEX $TOTAL

Is eqivalent to

@goal goal_name@a.txt
 echo a.txt 0 2

@goal goal_name@b.txt
 echo b.txt 1 2

iff

$ ls
a.txt b.txt

Also allowed form

@goal @glob *.txt
 echo $ITEM $INDEX $TOTAL

as equivalent for

@goal a.txt
 echo a.txt 0 2

@goal b.txt
 echo b.txt 1 2

Rationale

1. This will allow have multiple glob goals for same set of files
2. This will allow multiple globs per goal
   • Discarded: this is big over-complication in terms of UX and implementation.

Discarded design attempt

@goal goal_name
@glob FILE *.txt
 echo $FILE $FILE_INDEX $FILE_TOTAL

Is eqivalent to

@goal goal_name-a.txt
 echo a.txt 0 2

@goal goal_name-b.txt
 echo b.txt 1 2

iff

$ ls
a.txt b.txt