Change default value of resolution_factor in DrawRects.cfg

[708yamaguchi]

In draw_rects.cpp, if we use the default value of resolution_factor (2.0), the output image size will be twice as large as the input.
This resize is done in the following parts:

jsk_recognition/jsk_perception/src/draw_rects.cpp

Lines 159 to 161 in a6abfcc

	cv::resize(cv_img->image, img, cv::Size(),
	resolution_factor_, resolution_factor_,
	interpolation_method_);

cv::resize() documentation:
http://opencv.jp/opencv-2svn/cpp/geometric_image_transformations.html#cv-resize

Changing the default values could be disruptive, but I think the current default values are likely to be misleading.