ggsave (.svg) transforms geom_text integer to float #626

https://github.com/JetBrains/lets-plot/issues/626

from lets_plot import *
from IPython.display import SVG, Image, HTML
LetsPlot.setup_html()

d = {
    'x': [0],
    'y': [0],
    'label': [777]
}
p = ggplot(d) + geom_label(aes(x='x', y='y', label='label'))
p

display(SVG(ggsave(p, 'issue_626.svg')))