Resolve "FEATURE: alias groupping"

The current commit works with the following test-script. Maybe you want to test a bit?

from myplotlib import *
from myplotlib import test
from myplotlib.test import readStupidData

data = readStupidData()

fig = test.FigTest2(data)

print('tagged_keywords: ', fig._tagged_keywords)
print('aliases: ', fig.aliases)

ax1 = fig.get_axes_by_name('p1')
ax2 = fig.get_axes_by_name('p2')

print('ax1.keywords: ', ax1.keywords)
print('ax2.keywords: ', ax2.keywords)

fig.update(xRange=(0, 1))

print('ax1.keywords: ', ax1.keywords)
print('ax2.keywords: ', ax2.keywords)

fig.update(xRange=(0, 1), p1_xRange=(8, 88))

print('ax1.keywords: ', ax1.keywords)
print('ax2.keywords: ', ax2.keywords)