Only squish/censor finite values
Better behavior for scientific and comma.
Fixes #7
Better(?) zero_range.  Fixes #6
Doc fixes for scales
Version bump
Better log breaks
Preserve existing alpha when alpha is missing
Doc update
Extended breaks function
Add missing import
dollar will not use scientific notation and only give 2 or 0 decimals

As it was written, dollar (dollar_format, its generator
function) could give scientific notation for large round
values and could give a single decimal place for numbers
of a certain magnitude. Bot of these have been fixed.
Additionally, documentation has been updated to reflect
when cents are displayed, and the dollar_format function
now takes an argument which controls the threshold
value for displaying cents. Tests specific for dollar
were added.

Examples of old and new behavior are below:

d> x <- c(100, 0.23, 1.456565, 2e3); dollar(x); dollar_new(x)
[1] "$100.00"   "$0.23"     "$1.46"     "$2,000.00"
[1] "$100.00"   "$0.23"     "$1.46"     "$2,000.00"
d> x <- c(1:10 * 10); dollar(x); dollar_new(x)
 [1] "$10"  "$20"  "$30"  "$40"  "$50"  "$60"  "$70"  "$80"  "$90"  "$100"
 [1] "$10"  "$20"  "$30"  "$40"  "$50"  "$60"  "$70"  "$80"  "$90"  "$100"
d> x <- (1:10 * 10) + 0.01; dollar(x); dollar_new(x)
 [1] "$10.01"  "$20.01"  "$30.01"  "$40.01"  "$50.01"  "$60.01"  "$70.01" 
 [8] "$80.01"  "$90.01"  "$100.01"
 [1] "$10.01"  "$20.01"  "$30.01"  "$40.01"  "$50.01"  "$60.01"  "$70.01" 
 [8] "$80.01"  "$90.01"  "$100.01"
d> x <- (1:10 * 10) + 0.001; dollar(x); dollar_new(x)
 [1] "$10"  "$20"  "$30"  "$40"  "$50"  "$60"  "$70"  "$80"  "$90"  "$100"
 [1] "$10"  "$20"  "$30"  "$40"  "$50"  "$60"  "$70"  "$80"  "$90"  "$100"
d> x <- 10^(1:8); dollar(x); dollar_new(x)
[1] "$1e+01" "$1e+02" "$1e+03" "$1e+04" "$1e+05" "$1e+06" "$1e+07" "$1e+08"
[1] "$10"          "$100"         "$1,000"       "$10,000"      "$100,000"    
[6] "$1,000,000"   "$10,000,000"  "$100,000,000"
d> x <- seq(10111.11, 100000, 10111.11); dollar(x); dollar_new(x)
[1] "$10,111.11" "$20,222.22" "$30,333.33" "$40,444.44" "$50,555.55"
[6] "$60,666.66" "$70,777.77" "$80,888.88" "$90,999.99"
[1] "$10,111.11" "$20,222.22" "$30,333.33" "$40,444.44" "$50,555.55"
[6] "$60,666.66" "$70,777.77" "$80,888.88" "$90,999.99"
d> x <- seq(101111.11, 1000000, 101111.11); dollar(x); dollar_new(x)
[1] "$101,111.1" "$202,222.2" "$303,333.3" "$404,444.4" "$505,555.5"
[6] "$606,666.7" "$707,777.8" "$808,888.9" "$910,000.0"
[1] "$101,111" "$202,222" "$303,333" "$404,444" "$505,556" "$606,667" "$707,778"
[8] "$808,889" "$910,000"
d> x <- seq(101111, 1000000, 101111); dollar(x); dollar_new(x)
[1] "$101,111" "$202,222" "$303,333" "$404,444" "$505,555" "$606,666" "$707,777"
[8] "$808,888" "$909,999"
[1] "$101,111" "$202,222" "$303,333" "$404,444" "$505,555" "$606,666" "$707,777"
[8] "$808,888" "$909,999"
d> x <- seq(10111111.11, 100000000, 10111111.11); dollar(x); dollar_new(x)
[1] "$10,111,111" "$20,222,222" "$30,333,333" "$40,444,444" "$50,555,556"
[6] "$60,666,667" "$70,777,778" "$80,888,889" "$91,000,000"
[1] "$10,111,111" "$20,222,222" "$30,333,333" "$40,444,444" "$50,555,556"
[6] "$60,666,667" "$70,777,778" "$80,888,889" "$91,000,000"
d> x <- (1:10) * 100000; dollar(x); dollar_new(x) 
 [1] "$1e+05" "$2e+05" "$3e+05" "$4e+05" "$5e+05" "$6e+05" "$7e+05" "$8e+05"
 [9] "$9e+05" "$1e+06"
 [1] "$100,000"   "$200,000"   "$300,000"   "$400,000"   "$500,000"  
 [6] "$600,000"   "$700,000"   "$800,000"   "$900,000"   "$1,000,000"
d> x <- ((1:10) * 100000) + 0.01; dollar(x); dollar_new(x)
 [1] "$1e+05" "$2e+05" "$3e+05" "$4e+05" "$5e+05" "$6e+05" "$7e+05" "$8e+05"
 [9] "$9e+05" "$1e+06"
 [1] "$100,000"   "$200,000"   "$300,000"   "$400,000"   "$500,000"  
 [6] "$600,000"   "$700,000"   "$800,000"   "$900,000"   "$1,000,000"
Merge pull request #17 from BrianDiggs/dollar-format

dollar will not use scientific notation and only give 2 or 0 decimals
Check for zero-length input in gradient pal
Version bump for ggplot2
Fix bug in alpha function.
Version bump for ggplot2