Added runtime set support for some attribs

* TextBox Read/Write Attributes:
text
font_color
background_color
border_color
border_stroke_width
pos
align_horz
align_vert
grid_color
grid_stroke_width
grid_horz_justification
grid_vert_justification

* Read Only Attributes (Currently):
window
font_name
bold
italic
font_size
dpi
line_spacing
line_spacing_units
size
textgrid_shape
units
color_space
opacity
autoLog
interpolate