Merge pull request #1 from Nebuleon/master

Use integer arithmetic and fraction reduction to determine the resizing ratio
Merge pull request #2 from Nebuleon/master

Convert all remaining functions to use integers.
Merge pull request #3 from Nebuleon/master

Add nearest-neighbor interpolation
Merge pull request #4 from Nebuleon/master

Set the coefficient register to 0x1 (H/V_CONF) alone first.
Merge pull request #5 from Nebuleon/master

Add input and output stride parameters.
Stop the IPU before disabling its clock
Clear the REG_CTRL register instead of setting its RST bit

Strangely enough, waiting in a long enough usleep() right after
setting the RST bit would prevent the IPU from outputing an image.

On the other hand, clearing the REG_CTRL register does not have this
surprising behaviour. Since all the registers we use will obtain
new values anyway, it is not absolutely necesary to reset them.
Merge https://github.com/gcwnow/tests
Reorder register writes according to the IPU documentation.

The registers are now set in the following order:
* the horizontal and vertical resizing enabled bits in REG_CTRL;
* the horizontal and vertical coefficient counts in REG_RSZ_COEF_INDEX;
* the source and destination image dimensions in REG_IN_FM_GS and REG_OUT_GS;
* the source and destination image stride (bytes per line) in REG_Y_STRIDE and REG_OUT_STRIDE;
* the horizontal and vertical coefficient lookup table in REG_HRSZ_COEF_LUT and REG_VRSZ_COEF_LUT.

Having the resizing enabled first allows the coefficient counts to apply properly; having the coefficient counts set first allows the coefficient configuration to apply properly.

Downscaling and upscaling are more stable with this change.
Merge pull request #7 from Nebuleon/register-ordering

Reorder register writes according to the IPU documentation.
Merge pull request #6 from Nebuleon/master

Changes in read_reg and write_reg
Increase the delays between coefficient writes

20ms seems to be the minimum between two consecutive writes.
Additionally, another 20ms write before the very first write
seems also necesary.
Merge https://github.com/gcwnow/tests