Workaround for Julia bug

Switching the colormaps_sequential and colormaps_diverging values from tuples to vectors works around the Julia bug JuliaLang/julia#8631, solving #68 and JuliaIO/HDF5.jl#160.

src/maps_data.jl

@@ -6,16 +6,16 @@
 const colormaps_sequential = Compat.@Dict(
     #single hue
     #name        hue   w     d     c     s     b     wcolor      dcolor
-    "blues"   => (255, 0.3,  0.25, 0.88, 0.6,  0.75, RGB(1,1,0), RGB(0,0,1)),
-    "greens"  => (120, 0.15, 0.18, 0.88, 0.55, 0.9,  RGB(1,1,0), RGB(0,0,1)),
-    "grays"   => (0,   0.0,  0.0,  1.0,  0.0,  0.75, RGB(1,1,0), RGB(0,0,1)),
-    "oranges" => (20,  0.5,  0.4,  0.83, 0.95, 0.85, RGB(1,1,0), RGB(1,0,0)),
-    "purples" => (265, 0.15, 0.2,  0.88, 0.5,  0.7,  RGB(1,0,1), RGB(1,0,0)),
-    "reds"    => (12,  0.15, 0.25, 0.8,  0.85, 0.6,  RGB(1,1,0), RGB(0.3,0.1,0.1))
+    "blues"   => [255, 0.3,  0.25, 0.88, 0.6,  0.75, RGB(1,1,0), RGB(0,0,1)],
+    "greens"  => [120, 0.15, 0.18, 0.88, 0.55, 0.9,  RGB(1,1,0), RGB(0,0,1)],
+    "grays"   => [0,   0.0,  0.0,  1.0,  0.0,  0.75, RGB(1,1,0), RGB(0,0,1)],
+    "oranges" => [20,  0.5,  0.4,  0.83, 0.95, 0.85, RGB(1,1,0), RGB(1,0,0)],
+    "purples" => [265, 0.15, 0.2,  0.88, 0.5,  0.7,  RGB(1,0,1), RGB(1,0,0)],
+    "reds"    => [12,  0.15, 0.25, 0.8,  0.85, 0.6,  RGB(1,1,0), RGB(0.3,0.1,0.1)]
 )
 
 const colormaps_diverging = Compat.@Dict(
     #name         h1   h2    w     d1    d2    c      s     b      wcolor      dcolor      dcolor2
-    "rdbu"    => (12,  255,  0.2,  0.6,  0.0,  0.85,  0.6,  0.65,  RGB(1,1,0), RGB(1,0,0), RGB(0,0,1))
+    "rdbu"    => [12,  255,  0.2,  0.6,  0.0,  0.85,  0.6,  0.65,  RGB(1,1,0), RGB(1,0,0), RGB(0,0,1)]
 )